Hybrid Electric Propulsion System Load Sharing

Abstract

A method for operating a hybrid electric propulsion system is provided, the system having a first engine, a second engine, a first electric machine coupled to the first engine, and a second electric machine coupled to one of the first engine or the second engine. The method includes: receiving data indicating a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin, a second parameter operating margin, or both; determining a load distribution between the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both; and transmitting a first amount of power to or from the first electric machine and transmitting a second amount of power to or from the second electric machine in response to the determined load distribution.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a non-provisional application and claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 63 / 072,573 filed on August 31, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present subject matter generally relates to hybrid-electric aircraft propulsion systems, hybrid power systems for aircraft and aircraft engines, and methods of operating the same. Background Art

[0004] Conventional commercial aircraft generally include a fuselage, a pair of wings, and a propulsion system that provides thrust. The propulsion system generally includes at least two aircraft engines, such as turbofan jet engines. Each turbofan jet engine is generally mounted to a corresponding one of the wings of the aircraft, such as in a hanging position below the wing, separate from the wing and the fuselage.

[0005] Hybrid electric propulsion systems are being developed to improve the efficiency of conventional commercial aircraft. Various hybrid electric propulsion systems include an electric motor driven by one of the aircraft engines. The inventors of the present disclosure have proposed various configurations and / or methods to improve currently known hybrid electric propulsion systems. Summary of the invention

[0006] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0007] In an exemplary aspect of the present disclosure, a method for operating a hybrid electric propulsion system for an aircraft is provided. The hybrid electric propulsion system includes a first engine, a second engine, a first motor coupled to the first engine, and a second motor coupled to one of the first engine or the second engine. The method includes: receiving data indicating a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin, a second parameter operating margin, or both; determining a load distribution between the first engine, the second engine, or both, or the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both; and transmitting a first amount of power to or from the first motor and transmitting a second amount of power to or from the second motor in response to the determined load distribution.

[0008] These and other features, aspects and advantages of the present invention will be better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0010] Figure 1 is a top view of an aircraft according to various exemplary embodiments of the present disclosure.

[0011] Figure 2 yes Figure 1 A side view of an exemplary aircraft.

[0012] Figure 3 is a schematic cross-sectional view of a gas turbine engine according to an exemplary embodiment of the present disclosure, which gas turbine engine may be mounted to Figure 1 An exemplary aircraft of the invention.

[0013] Figure 4 is a schematic diagram of a propulsion system according to an exemplary embodiment of the present disclosure.

[0014] Figure 5 is a graphical representation of load distribution according to an exemplary aspect of the present disclosure.

[0015] Figure 6 is a flow chart of a method for operating a hybrid electric propulsion system according to an exemplary aspect of the present disclosure.

[0016] Figure 7 is a flow chart of a method for operating a hybrid electric propulsion system according to another exemplary aspect of the present disclosure. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to the present embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to the features in the drawings. The same or similar reference numerals in the drawings and description have been used to refer to the same or similar parts of the present invention.

[0018] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of each component.

[0019] The terms "forward" and "rearward" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, for a gas turbine engine, forward refers to a position closer to the engine inlet, while rearward refers to a position closer to the engine nozzle or exhaust.

[0020] The terms "upstream" and "downstream" refer to the relative directions of flow in a path. For example, with respect to fluid flow, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing. However, the terms "upstream" and "downstream" as used herein may also refer to electrical current.

[0021] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0022] Approximate language used in the entire specification and claims is applied to modify any quantitative representation that can allow variation without causing the basic function associated therewith to change. Therefore, the value modified by terms such as "about", "approximately" and "substantially" is not limited to the specified exact value. In at least some cases, approximate language can correspond to the accuracy of the instrument used to measure the value, or the accuracy of the method or machine used to construct or manufacture parts and / or systems. In at least some cases, approximate language can correspond to the accuracy of the instrument used to measure the value, or the accuracy of the method or machine used to construct or manufacture parts and / or systems. For example, approximate language can refer to within 1%, 2%, 4%, 5%, 10%, 15% or 20% of the endpoint of a single value, a range of values ​​and / or a range of limited values.

[0023] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, such ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0024] In certain exemplary aspects of the present disclosure, systems and methods for standardizing engine operating parameter margins between two or more engines of a hybrid electric propulsion system of an aircraft vehicle are provided. For example, in an exemplary aspect of the present disclosure, the method may receive data indicating a first engine operating parameter of a first engine and a second engine operating parameter of a second engine, and may also determine a first engine operating parameter margin of the first engine and a second engine operating parameter margin of the second engine. The engine operating parameters and engine operating parameter margins may be fuel flow and fuel flow margins, exhaust gas temperature ("EGT") and EGT margins, etc. The exemplary method may then determine a load distribution based on the first and second engine operating parameter margins, and transmit a first power amount to or from a first motor (coupled to a first engine) in response to and according to the determined load distribution, and transmit a second power amount to or from a second motor (coupled to one of the first engine or the second engine) in response to and according to the determined load distribution.

[0025] For example only, the second electric machine may be coupled to the second engine, and the method may determine that the first operating parameter margin is less than the second operating parameter margin. For example, if EGT is the first and second operating parameters, it may be determined that the EGT margin of the first engine (measured from the actual EGT of the first engine to the EGT limit of the first engine) is less than the EGT margin of the second engine (measured from the actual EGT of the second engine to the EGT limit of the second engine).

[0026] In response, the method may determine a load distribution to normalize the EGT margins of the first and second engines. For example, the determined load distribution may dictate that the second engine should transfer some power to the first engine (via the first and second electric machines) such that the EGT margin of the first engine is increased and the EGT margin of the second engine is decreased, normalizing the two EGT margins.

[0027] Additionally or alternatively, the determined load distribution may dictate that a power source external to the first and second engines should transfer more power to the first engine (via the first motor) rather than to the second engine (via the second motor), such that the EGT margin of the first engine is increased relative to the EGT margin of the second engine, thereby normalizing the two margins.

[0028] Additionally or alternatively, the determined load distribution may dictate that the first engine (via the first electric machine) should transfer less power to a power absorber (external to the first and second engines, such as an aircraft load) than the second engine (via the second electric machine), such that the EGT margin of the first engine is increased relative to the EGT margin of the second engine, thereby normalizing the two margins.

[0029] However, in other example aspects, the first electric machine may be coupled to a low pressure system of the first engine and the second electric machine may be coupled to a high pressure system of the first engine, and the method may determine that the first EGT margin is different from the second EGT margin. In response, the determined load distribution may dictate that some power should be transferred between the high pressure system and the low pressure system to the first engine (via the first and second electric machines) such that the EGT margin of the first engine is increased or decreased relative to the EGT margin of the second engine, thereby normalizing the two margins.

[0030] However, in other examples, the first and second operating parameters and margins may be based, for example, on fuel flow to the respective engines or any other suitable parameter.

[0031] Referring now to the drawings, in which like numerals represent like elements throughout the several views, Figure 1 A schematic top view of an aircraft 10 having a hybrid electric propulsion system 50 according to yet another exemplary embodiment of the present disclosure is provided, and Figure 2 Provided Figure 1 A schematic side view of an exemplary aircraft of FIG. 1 is a schematic side view of an exemplary aircraft of FIG. 1 . In particular, Figure 1 and Figure 2 An aircraft 10 is depicted that defines a longitudinal centerline 14 extending therethrough, a lateral direction L, a front end 16, and a rear end 18. The aircraft 10 includes a fuselage 12, a tail 19, a first wing 20, and a second wing 22. The first and second wings 20, 22 each extend laterally outward relative to the longitudinal centerline 14. The first wing 20 and a portion of the fuselage 12 together define a first side 24 of the aircraft 10, and the second wing 22 and another portion of the fuselage 12 together define a second side 26 of the aircraft 10. For the depicted embodiment, the first side 24 of the aircraft 10 is configured as the port side of the aircraft 10, and the second side 26 of the aircraft 10 is configured as the starboard side of the aircraft 10.

[0032] Each of the wings 20, 22 of the depicted exemplary embodiment includes one or more leading edge flaps 28 and one or more trailing edge flaps 30. The aircraft 10 also includes, or more precisely, the tail 19 of the aircraft 10 includes a vertical stabilizer 32 with a rudder flap (not shown) for yaw control and a pair of horizontal stabilizers 34, each of which has an elevator flap 36 for pitch control. The fuselage 12 additionally includes an outer surface or skin 38. However, it should be understood that in other exemplary embodiments of the present disclosure, the aircraft 10 may additionally or alternatively include any other suitable configuration. For example, in other embodiments, the aircraft 10 may include a stabilizer of any other configuration.

[0033] Figure 1The exemplary aircraft 10 further includes a hybrid electric propulsion system 50 having a first gas turbine engine 100A, a second gas turbine engine 100B, and an electrical energy storage unit 55. For the depicted embodiment, the first gas turbine engine 100A and the second gas turbine engine 100B are both configured in an underwing mounted configuration.

[0034] Now also refer to Figure 3 , a schematic cross-sectional view of a gas turbine engine 100 is provided. Figure 1 and Figure 2 The first and second gas turbine engines 100A, 100B depicted in FIG. 1 may be configured to operate in a manner similar to that of FIG. Figure 3 The exemplary engine 100 is constructed in a similar manner.

[0035] Figure 3 The gas turbine engine 100 is more specifically configured as a turbofan engine 100, including a turbine 102 and a fan 104. Figure 3 As shown, turbofan engine 100 defines an axial direction A1 (extending parallel to a longitudinal centerline 101 provided for reference) and a radial direction R1 . As depicted, turbofan engine 100 includes a fan 104 and a turbine 102 disposed downstream of fan 104 .

[0036] The depicted exemplary turbomachine 102 generally includes a substantially tubular casing 106 defining an annular inlet 108. The casing 106 encloses, in serial flow relationship: a compressor section including a supercharger or low pressure (LP) compressor 110 and a high pressure (HP) compressor 112; a combustion section 114; a turbine section including a first high pressure (HP) turbine 116 and a second low pressure (LP) turbine 118; and an ejection exhaust nozzle section 120. The compressor section, combustion section 114, and turbine section together at least partially define a core air flow path 121.

[0037] The exemplary turbine 102 of the turbofan engine 100 also includes one or more shafts that can rotate with at least a portion of the turbine section and, for the depicted embodiment, with at least a portion of the compressor section. More specifically, for the depicted embodiment, the turbofan engine 100 includes a high pressure (HP) shaft or spool 122 that drivingly connects the HP turbine 116 to the HP compressor 112. In addition, the exemplary turbofan engine 100 includes a low pressure (LP) shaft or spool 124 that drivingly connects the LP turbine 118 to the LP compressor 110.

[0038] In addition, the depicted exemplary fan 104 is configured as a variable pitch fan having a plurality of fan blades 128 coupled to a disk 130 in a spaced-apart manner. The fan blades 128 extend outwardly from the disk 130 generally in a radial direction R1. Each fan blade 128 can rotate relative to the disk 130 about a respective pitch axis P1 by virtue of the fan blades 128 being operably coupled to a suitable actuation member 132, the actuation member 132 being configured to collectively vary the pitch of the fan blades 128. The fan 104 is mechanically coupled to the LP shaft 124 such that the fan 104 is mechanically driven by the second LP turbine 118. More specifically, the fan 104 including the fan blades 128, the disk 130, and the actuation member 132 is mechanically coupled to the LP shaft 124 through a power gearbox 134, and can rotate about the longitudinal axis 101 across the power gearbox 134 through the LP shaft 124. The power gearbox 134 includes a plurality of gears for reducing the rotational speed of the LP shaft 124 to a more efficient rotating fan speed. Thus, the fan 104 is powered by the LP system of the turbomachine 102 (including the LP turbine 118).

[0039] Still reference Figure 3 In an exemplary embodiment of the present invention, the disk 130 is covered by a rotatable front hub 136 that is aerodynamically shaped to facilitate airflow through a plurality of fan blades 128. In addition, the turbofan engine 100 includes an annular fan case or outer nacelle 138 that circumferentially surrounds at least a portion of the fan 104 and / or the turbine 102. Therefore, the depicted exemplary turbofan engine 100 may be referred to as a "ducted" turbofan engine. In addition, the nacelle 138 is supported relative to the turbine 102 by a plurality of circumferentially spaced outlet guide vanes 140. A downstream section 142 of the nacelle 138 extends over an outer portion of the turbine 102 to define a bypass airflow passage 144 therebetween.

[0040] Still reference Figure 3, the hybrid electric propulsion system 50 further includes an electric machine, which for the depicted embodiment is configured as an electric motor / generator 56. For the depicted embodiment, the electric motor / generator 56 is positioned within the turbine 102 of the turbofan engine 100 and is mechanically connected to one of the shafts of the turbofan engine 100. More specifically, for the depicted embodiment, the electric motor / generator 56 is a first electric motor / generator 56-1, and is positioned inside the core air flow path 121, driven by the first HP turbine 116 through the HP shaft 122. The first electric motor / generator 56-1 is configured to convert the mechanical power of the HP shaft 122 into electricity during certain operations, and is further configured to convert electricity into mechanical power in other operations. Therefore, the first electric motor / generator 56-1 can be powered by the HP system (including the HP turbine 116) of the turbine 102 during certain operations, and can provide power to the HP system during other operations.

[0041] Further to the depicted embodiment, the hybrid electric propulsion system 50 additionally includes a second motor / generator 56-2. The second motor / generator 56-2 is configured to convert the mechanical power of the LP shaft 124 into electrical power during certain operations, and is further configured to convert electrical power into mechanical power during other operations. Thus, the second motor / generator 56-2 can be powered by the LP system (including the LP turbine 118) of the turbomachine 102 during certain operations, and can power the LP system during other operations.

[0042] It is worth noting that the motor / generators 56-1, 56-2 can be relatively powerful motor / generators. For example, during certain operations, the motor / generators 56-1, 56-2 can be configured to generate at least about 50 kilowatts of electricity or at least about 65 horsepower of mechanical power. However, in other embodiments, the motor / generators 56-1, 56-2 can generate other amounts of power.

[0043] However, it should be understood that in other exemplary embodiments, the motor / generators 56-1, 56-2 may alternatively be positioned at any other suitable location or elsewhere within the turbine 102, and may be, for example, powered in any other suitable manner. For example, in other embodiments, the first motor / generator 56-1 may be mounted coaxially with the HP shaft 122 within the turbine section, or alternatively may be offset from the HP shaft 122 and driven by a suitable gear train. Similarly, in other embodiments, the second motor / generator 56-2 may be mounted coaxially with the LP shaft 124 within the compressor section, or alternatively may be offset from the LP shaft 124 and driven by a suitable gear train. Additionally or alternatively, in still other embodiments, the hybrid electric propulsion system 50 may not include both the first and second motor / generators 56-1, 56-2, but may instead include only one of such motor / generators 56-1, 56-2.

[0044] It should also be understood that in other exemplary embodiments, Figure 3 The exemplary turbofan engine 100 shown may have any other suitable configuration. For example, in other exemplary embodiments, the fan 104 may not be a variable pitch fan, and further, in other exemplary embodiments, the LP shaft 124 may be directly mechanically coupled to the fan 104 (i.e., the turbofan engine 100 may not include a gearbox 134). In addition, it should be understood that in other exemplary embodiments, the first propeller 52 may include any other suitable type of engine. For example, in other embodiments, the turbofan engine 100 may alternatively be configured as a turboprop engine or a non-ducted turbofan engine. In addition, in other embodiments, the turbofan engine 100 may alternatively be configured as any other suitable internal combustion engine for driving the motor / generator 56-1, 56-2. For example, in other embodiments, the turbofan engine may be configured as a turboshaft engine, or any other suitable internal combustion engine (e.g., a non-ducted, open rotor engine).

[0045] Still refer to Figure 1 and Figure 2, the turbofan engine 100 also includes a controller 150 and one or more sensors (although not shown). The controller 150 may be a full authority digital engine control system, also known as a FADEC. The controller 150 of the turbofan engine 100 may be configured to control the operation of, for example, the actuating member 132, the fuel delivery system to the combustion section 114 (not shown), and the like. In addition, the controller 150 may be operably connected to one or more sensors to receive data from the sensors and determine various operating parameters of the turbofan engine 100. For example, the controller 150 may determine one or more of the exhaust temperature, the rotational speed of the core (i.e., the rotational speed of the HP system), the compressor discharge temperature, and the like. In addition, return to reference Figure 1 , the controller 150 of the turbofan engine 100 is operably connected to the controller 72 of the hybrid electric propulsion system 50. In addition, as will be appreciated, the controller 72 may also be operably connected to one or more of the first and second gas turbine engines 100A, 100B, the energy storage unit 55, etc. via a suitable wired or wireless communication system (depicted in dashed lines).

[0046] Special return reference Figure 1 and Figure 2 The electrical system of the hybrid electric propulsion system 50 includes one or more electric machines (e.g., schematically depicted electric machine 56A) mechanically coupled to the first gas turbine engine 100A and one or more electric machines (e.g., schematically depicted electric machine 56B) mechanically coupled to the second gas turbine engine 100B. Although schematically depicted as being external to the respective gas turbine engines 100A, 100B, in certain embodiments, the electric motor / generators 56A, 56B may be positioned within the gas turbine engines 100A, 100B (see, e.g., Figure 3 ) in a corresponding one of the motors 100A and 100B. In addition, although each gas turbine engine 100A, 100B is depicted as having a single motor / generator, in certain embodiments, a plurality of motor / generators 56A, 56B may be provided for each engine (e.g., the gas turbine engine 100A having motor / generators 56A-1, 56A-2 and the gas turbine engine 100B having motor / generators 56B-1, 56B-2).

[0047] In addition, as mentioned above Figure 3 Briefly mentioned, Figure 1 and Figure 2In an embodiment of the hybrid electric propulsion assembly 50, the hybrid electric propulsion assembly 50 further includes a controller 72. It should be understood that the energy storage unit 55 can be configured to receive power from one or both of the first motor / generator 56A and the second motor / generator 56B under certain operating conditions, and can be further configured to provide stored power to one or both of the first motor / generator 56A and the second motor / generator 56B under certain operating conditions. In addition, the controller 72 is operably connected to the turbofan engines 100A, 100B, the motor / generators 56A, 56B, and the energy storage unit 55 to control the operation of the hybrid electric propulsion system 50 during various operating conditions and selectively electrically connect components of the hybrid electric propulsion system 50, for example.

[0048] Additionally, the controller 72 may communicate with one or more aircraft controllers to receive data indicating that the aircraft requires power, and in response may provide power from one or more of the motor / generators 56A, 56B and the energy storage unit 55 to the aircraft loads 74 .

[0049] However, it should be understood that in other exemplary embodiments of the present disclosure, any other suitable aircraft 10 may be provided, which has a hybrid electric propulsion system 50 configured in any other suitable manner. For example, in other embodiments, the turbofan engines 100A, 100B may be configured as any other suitable internal combustion engine (e.g., a turboprop engine, a non-ducted turbofan engine, a turboshaft engine, a turbojet engine, etc.), and may be installed at any other suitable location.

[0050] Furthermore, in other exemplary embodiments, the exemplary hybrid electric propulsion system 50 may have other configurations. For example, referring now briefly to Figure 4 , a schematic diagram of a hybrid electric propulsion system 50 according to yet another exemplary embodiment of the present disclosure is provided. Figure 4 The exemplary hybrid electric propulsion system 50 depicted in FIG. 5 may be similar to the one described above with reference to FIG. Figures 1 to 3 One or more exemplary hybrid-electric propulsion systems 50 are described.

[0051] For example, Figure 4The exemplary hybrid electric propulsion system 50 generally includes a first propeller 52 and a second propeller 54. The first propeller 52 generally includes a first engine 100A having a first turbine 102A and a first propeller 104A, and a second engine 100B having a second turbine 102B and a second propeller 104B. Each of the first and second turbines 102A, 102B generally includes: a low-pressure system having a low-pressure compressor 110 drivingly coupled to a low-pressure turbine 118 via a low-pressure shaft (not labeled); and a high-pressure system having a high-pressure compressor 112 drivingly coupled to a high-pressure turbine 116 via a high-pressure shaft (not labeled).

[0052] In addition, the first propeller 104A is drivingly coupled to the low pressure system of the first turbine 102A, and the second propeller 104B is drivingly coupled to the low pressure system of the second turbine 102B. In certain exemplary embodiments, the first propeller 104A and the first turbine 102A may be configured as a first turbofan engine, and similarly, the second propeller 104B and the second turbine 102B may be configured as a second turbofan engine (see, e.g., Figure 3 ). However, alternatively, these components may alternatively be configured as components of a turboprop engine or any other suitable turbine-driven propulsion device.

[0053] also, Figure 4 The hybrid electric propulsion system 50 further includes an electrical system. More specifically, the hybrid electric propulsion system 50 includes one or more motors operable with the first engine 100A, the second engine 100B, or both, and an electric energy storage unit 55 electrically connected to one or more of the motors.

[0054] In particular, for the depicted embodiment, the hybrid electric propulsion system 50 includes first and second electric machines 56A- 1 and 56A- 2 operable with the first engine 100A, and first and second electric machines 56B- 1 and 56B- 2 operable with the second engine 100B.

[0055] More specifically, for the depicted embodiment, the first electric machines 56A-1, 56B-1 are each coupled to the high pressure system of the respective turbine 102A, 102B (see Figure 2 The second electric machines 56A-2, 56B-2 are each coupled to the low pressure system of the corresponding turbine 102A, 102B (see Figure 2 Motor 56-2 in).

[0056] Also like Figure 4As shown, the exemplary hybrid electric propulsion system 50 also includes an electric bus 58. The first motor 56A-1, 56A-2, the second motor 56B-1, 56B-2, and the electric energy storage unit 55 can each be electrically connected to each other through one or more wires 60 of the electric bus 58. For example, the electric bus 58 can include various switches or other power electronic devices that can be moved to selectively electrically connect various components of the hybrid electric propulsion system 50, and optionally convert or regulate such power transmitted therethrough. The various switches and other power electronic devices can be operably connected to the controller so that the controller can control the power flowing to and / or from the first motor 56A-1, 56A-2, the second motor 56B-1, 56B-2, and the electric energy storage unit 55.

[0057] In addition, as also shown, the power bus 58 is electrically connected to one or more aircraft systems 74 for providing power from one or more of the first motors 56A-1, 56A-2, the second motors 56B-1, 56B-2, and the electrical energy storage unit 55 to the one or more aircraft systems 74. The one or more aircraft systems 74 may include, for example, environmental control, aircraft control, hydraulic systems, pumps, de-icing systems, navigation, lighting, heating, etc.

[0058] also, Figure 4 The system depicted in FIG. 1 includes a control system 152 having a supervisory controller 154 (which may be similar to the controller 72 described above), a first gas turbine engine controller 156 (which may be, for example, a FADEC controller), and a second gas turbine engine controller 158 (which may also be, for example, a FADEC controller). The exemplary control system 152 may receive data indicating one or more operational parameters of the first gas turbine engine 100A, the second gas turbine engine 100B, or both. For example, the exemplary control system 152 may receive data indicating one or more fuel flows, one or more operating temperatures (e.g., exhaust gas temperature, compressor outlet temperature, turbine inlet temperature, etc.), one or more speeds of the gas turbine engine (e.g., speed of the low pressure system, speed of the high pressure system, speed of the fan / propeller, etc.), one or more shaft torques, one or more pressure measurements, one or more thrust outputs (which may be, for example, calculated values ​​based on a combination of fan / propeller speed and fan / propeller pitch angle), serial numbers or other unique component identifiers identifying components (e.g., of one or more engines), estimates or measurements of consumed components or remaining life or performance, any combination of these or calculated values ​​derived therefrom, and the like.

[0059] As will be appreciated, within a particular propulsion system for an aircraft, each gas turbine engine may define a different performance level due to, for example, the age of the engine, the date of the last maintenance, production variations, and a range of other factors. Due to variations in hardware quality and performance characteristics, each gas turbine engine may require a different amount of fuel or electricity to operate at a set speed or power setting (e.g., at idle or takeoff power). The amount of energy in the form of fuel or electricity required to operate at the set speed may affect the operating speed, temperature, and pressure, affecting the hardware degradation rate based on a combination of these characteristics, and setting the available margin for a particular engine to accelerate from that speed to a higher speed. For example, the amount of fuel required for a particular engine to operate at idle can set the margin for a particular engine to accelerate from idle to takeoff. In addition, the degree of degradation of the engine may also affect the stall margin, exhaust temperature margin, etc.

[0060] When the component quality or expected performance of one engine of a particular propulsion system changes due to degradation, damage caused by foreign object debris (FOD) passing through the core inlet in flight, or other factors, and the amount of change is different relative to another engine of the propulsion system (e.g., different overall degradation), this difference produces different acceleration margins within multiple engines 100A, 100B, as well as stall margins, exhaust temperature margins, hardware degradation rates, maximum sustainable power, etc.

[0061] Therefore, still refer to Figure 4 , it will be appreciated that the exemplary hybrid electric propulsion system 100 can accommodate these different hardware characteristics / degradations between the engines 100A, 100B to facilitate consistent margins for the engines 100A, 100B. More specifically, as noted, Figure 4 A schematic diagram of a hybrid electric propulsion system 50 is depicted that can accommodate differential degradation between the engines of the propulsion system 100 to facilitate constant margining of the engines 100A, 100B.

[0062] Figure 7 The exemplary control scheme schematically depicted in FIG. 1 generally receives data indicative of one or more parameters of the first gas turbine engine 100A and the second gas turbine engine 100B (e.g., one or more parameters indicative of the operating conditions of the engines and / or the health of the engines). In particular, for the depicted embodiment, the engine controllers 156, 158 may receive such data indicative of the one or more parameters and provide such data to the supervisory controller 154. The supervisory controller 154 includes a margin calculation module

[0063] For example, in an exemplary control scheme, the engine controllers 156, 158 may receive data indicating a fuel flow to the first gas turbine engine 100A and a fuel flow to the second gas turbine engine 100B. The first and second engine controllers 156, 158 may provide such data to the supervisory controller 154. The supervisory controller 154 may use such data to calculate or otherwise determine a margin for each engine 100A, 100B. More specifically, for the exemplary aspects depicted, the supervisory controller 154 includes a margin calculation module 160 to calculate or otherwise determine a margin for each engine 100A, 100B. The margin may be any margin parameter (e.g., fuel flow margin, temperature margin, etc.) indicating an available amount for an increased operating condition of the engine 100A, 100B.

[0064] However, it should be appreciated that in other exemplary aspects, the margins may alternatively be calculated or otherwise determined by the engine controllers 156 , 158 and provided to the supervisory controller 154 .

[0065] The supervisory controller 154 may also receive operating condition parameters through the operating condition module 162 that indicate desired operating conditions of the engine 100A, 100B, such as a desired power output of the engine.

[0066] Still reference Figure 4 The supervisory controller 154 may be further configured to determine a load distribution between the first and second engines 100A, 100B based on the calculated or otherwise determined margin information for each engine 100A, 100B from the margin module 160 and the desired operating condition data from the operating condition module 162. More specifically, the supervisory controller 154 includes a load distribution module 164 for receiving data from the margin module 160 and the operating condition module 162 and determining a load distribution for the first engine 100A, the second engine 100B, or both. The load distribution determined by the load distribution module 164 may include one or more of the following: (1) transferring power from the first engine 100A to the second engine 100B, or vice versa; (2) transferring power from the electrical energy storage unit 55, the first engine 100A, or both to the second engine 100B, or from the electrical energy storage unit 55, the second engine 100B, or both to the first engine 100A; (3) transferring power from the low pressure system of one of the first or second engines 100A, 100B to the high pressure system of the same engine, or vice versa; and / or (4) extracting different amounts of power from the first and second engines 100A, 100B. In this way, the system can normalize the margins of the two engines 100A, 100B.

[0067] For example, still refer to Figure 4, the margin used by the system may be a fuel flow margin. The engine controllers 156, 158 may receive data indicating a fuel flow margin (e.g., fuel flow to the respective engine) for each engine 100A, 100B and provide such information to the supervisory controller 154. The supervisory controller 154 may then calculate a first fuel flow margin for the first gas turbine engine 100A and a second fuel flow margin for the second gas turbine engine 100B.

[0068] Alternatively, the engine controllers 156 , 158 may receive data indicative of fuel flow to the first and second gas turbine engines 100A, 100B and calculate first and second fuel flow margins.

[0069] The supervisory controller 154 uses the first and second fuel flow margins and the received operating condition data of the engines 100A, 100B and can then calculate a load share to normalize the fuel flow margin of the first gas turbine engine 100A with the fuel flow margin of the second gas turbine engine 100B. The load share can be communicated to the first engine controller 156, the second engine controller 158 and / or the power bus 106 to implement the load share, or alternatively can communicate directly to the various power switches and power electronics of the electric machines 56A-1, 56A-2, 56B-1, 56B-2 and / or the power bus 58 to implement the load share.

[0070] In certain embodiments, the load distribution may define the amount of power to be extracted from the first gas turbine engine 100A via the electric machines 56A-1 and 56A-2 and from the second gas turbine engine 100B via the second electric machines 56B-1 and 56B-2 such that more power is extracted from the engine defining a lower or smaller fuel flow margin (indicating that it is the more degraded engine) than from the engine defining a higher or larger fuel flow margin. For example, the supervisory controller 154 may determine that the first fuel flow margin is less than the second flow margin, and in response, may calculate a load distribution that extracts more power from the second gas turbine engine 100B than from the first gas turbine engine 100A.

[0071] Additionally or alternatively, the control scheme may be configured such that power is not extracted from the more degraded engine, and / or such that power is provided to the more degraded engine. For example, the supervisory controller 154 may determine that the first fuel flow margin is less than the second flow margin, and in response, may calculate a load distribution that extracts power from the second gas turbine engine 100B and provides power to the first gas turbine engine 100A. The power provided to the more degraded engine may come from the less degraded engine. In addition, the power provided to the more degraded engine may be supplemented in small or major portions by an external source (e.g., an energy storage unit, an auxiliary power unit, etc.). For example, 5% to 95% of the power provided to the more degraded engine may be provided by an external source (e.g., an APU, an energy storage unit (located, for example, in an aircraft wing or fuselage, or in a pylon)).

[0072] Additionally or alternatively, the calculated load distribution may transfer power between the low pressure system and the high pressure system of a given gas turbine engine 100A, 100B. For example, the calculated load distribution may utilize the electric machines 56A-1, 56A-2, 56B-1, 56B-2 of a given gas turbine engine 100A, 100B to transfer power from the low pressure system and provide such extracted power to the high pressure system (or vice versa). This may allow for a reduction in idle speed, thereby improving component life, reducing fuel burn, and reducing idle thrust.

[0073] In certain exemplary embodiments, the load distribution may further specify the amount of engine bleed air that is extracted from one engine relative to the other engine. This may have an effect similar to changing the ratio of power extracted from the two engines. With respect to the bleed air extracted from the engines, bleed air that is not essential to engine performance (bleed air that is essential to engine performance typically includes, for example, air for turbine blade or oil cooling, maintaining operational stall line buffers, etc.) may be extracted less from the more degraded engine (bleed air that is not essential to engine performance may include air for servicing the aircraft environmental control system (ECS), de-icing and / or anti-icing systems, etc.), and more from the less degraded engine.

[0074] These control decisions may be based, at least in part, on the magnitude of the delta (i.e., difference) between any measured or calculated parameter or combination of parameters (e.g., fuel flow in one embodiment). These control decisions may be influenced by real-time data, in addition to or in lieu of, long-term tracking of this data as a function of power settings, environmental conditions, estimates of this data from tracking hardware quality, and the like.

[0075] For example, in certain exemplary embodiments, the parameters used herein may be based at least in part on one or more of the following: one or more fuel flows, one or more operating temperatures (e.g., exhaust temperature, compressor outlet temperature, turbine inlet temperature, etc.), one or more speeds of the gas turbine engine (e.g., rotational speed of the low pressure system, rotational speed of the high pressure system, rotational speed of the fan / propeller, etc.), one or more shaft torques, one or more pressure measurements, one or more thrust outputs (which may be, for example, calculated values ​​based on a combination of fan / propeller speed and fan / propeller pitch angle), a serial number or other unique component identifier identifying a component (e.g., of one or more engines), an estimate or measurement of consumed component or remaining life or performance, any combination of these or calculated values ​​derived therefrom, and the like.

[0076] Additionally or alternatively, the control scheme may still utilize temperature data (e.g., exhaust temperature data of the first and second gas turbine engines 100A, 100B) to determine the load distribution. For example, in addition or alternatively, the control scheme may receive exhaust temperature data from the first gas turbine engine 100A via the first engine controller 156 and exhaust temperature data from the second gas turbine engine 100B via the second engine controller 158, and utilize the data to calculate the first exhaust temperature margin and the second exhaust temperature margin.

[0077] For example, now refer to Figure 5 , graphically depicting an embodiment of the load sharing concept. Specifically, a first graph 170 on the left and a second graph 172 on the right both depict in red a relevant limitation at 174, such as a fuel flow limitation or a temperature limitation (e.g., an exhaust temperature limitation). The first graph 170 also depicts parameter levels for the first gas turbine engine 100A at line 176 and the same parameter levels for the second gas turbine engine 100B at line 178. The first graph 170 depicts these levels prior to any load sharing modification, such as, for example, without any load sharing between the first and second gas turbine engines 100A, 100B, or without power supplementation from any external source, or without load sharing between the low pressure and high pressure systems of one or both of the engines 100A, 100B, or without modification of power extraction from one or both of the engines 100A, 100B. As will be understood, the first gas turbine engine 100A ("Engine A") appears to be more degraded than the second gas turbine engine 100B ("Engine B") because the margin of Engine A between the parameter levels and parameter limits of the first gas turbine engine 100A is less than the margin of Engine B between the parameter levels and parameter limits of the second gas turbine engine 100B.

[0078] Based on this information, the control system 152 and supervisory controller 154 of the propulsion system 100 may calculate a load distribution to normalize the margins of the first and second engines 100A, 100B. For example, based on this information, the control system 152 and supervisory controller 154 of the propulsion system 100 may calculate a load distribution whereby a first amount of power is extracted from the first gas turbine engine 100A through one or both of the first LP electric machine 56A-1 and / or the first HP electric machine 56A-2, and a second amount of power is extracted from the second gas turbine engine 100B through one or both of the second LP electric machine 56B-1 and the second HP electric machine 56B-2, and whereby the first amount of power is less than the second amount of power (and may be zero or a negative amount, i.e., power may be alternately supplied from the first gas turbine engine 100A to the second gas turbine engine 100B, and vice versa).

[0079] like Figure 5 As shown in the second graph 154 on the right, after load sharing is applied, the margins between the parameters and parameter limits of the two engines 100A, 100B are substantially the same. This may result in more similar acceleration capabilities, stall margin capabilities, exhaust temperature margin capabilities, etc. between the two engines.

[0080] It is worth noting that the specific return reference Figure 4 , the control system 152 can further control the thrust output of the first and second gas turbine engines 100A, 100B in conjunction with the load sharing. For example, the first engine controller 156 can control the pitch and / or speed of the propeller of the first gas turbine engine 100A, and similarly, the second engine controller 158 can control the pitch and / or speed of the propeller of the second gas turbine engine 100B to ensure that the thrust output of the first gas turbine engine 100A is substantially equal to the thrust output of the second gas turbine engine 100B despite the load sharing applied between the two engines 100A, 100B. This configuration can help reduce the thrust asymmetric load of the aircraft and help synchronize the speed between the two engines.

[0081] Furthermore, in other exemplary embodiments, the control system 152 may control the thrust output of the first and second gas turbine engines 100A, 100B in any other suitable manner. For example, in other exemplary embodiments, the first and / or second gas turbine engines 100A, 100B may be configured as non-ducted turbofan engines having variable pitch exit guide vanes. For example, the engines 100A, 100B may be configured with Figure 3The engine 100 depicted in FIG. 1 is similarly configured, but may not include the nacelle 138, and the outlet guide vanes 140 may be operated with a variable pitch mechanism for changing the pitch of the outlet guide vanes 140. In this way, the variable outlet guide vanes 140 may affect the thrust output of the engine 100 without changing the fan speed. With such a configuration, the outlet guide vanes 140 may have any suitable length, spacing, number, etc. In such a configuration, in addition to or as an alternative to the pitch and / or speed of the propeller of the first gas turbine engine 100A, the first engine controller 156 may control the pitch of the variable outlet guide vanes of the first engine 100A. Similarly, in addition to or as an alternative to the pitch and / or speed of the propeller of the second gas turbine engine 100B, the second engine controller 158 may control the pitch of the variable outlet guide vanes of the second engine 100B. This may further ensure that despite the load sharing applied between the two engines 100A, 100B, the thrust output of the first gas turbine engine 100A is substantially equal to the thrust output of the second gas turbine engine 100B, and does not significantly affect the synchronous phasing and / or acoustic effects of the engines 100A, 100B.

[0082] It should be understood that this article refers to Figure 4 and Figure 5 The exemplary embodiments and control schemes described are provided as examples only. For example, in other embodiments, the first and second gas turbine engines 100A, 100B may not both include LP and HP motors; the control system 152 may not include a separate aircraft controller and the control decisions discussed herein may be made by the engine controller; the control system 152 may not use a separate engine controller, etc.

[0083] Furthermore, it should be appreciated that for the illustrated embodiment, the control scheme determines a first engine operating parameter margin and a second engine operating parameter margin, and subsequently determines a load distribution between the first engine and the second engine to reduce the difference between the first engine operating parameter margin and the second parameter operating margin. For example, in certain exemplary aspects, the control scheme may calculate the first and / or second engine operating parameter margins using one or more onboard embedded engine models within the supervisory controller 154, or by using parameters calculated from offline trends read via a configuration or data input plug-in.

[0084] However, in other exemplary aspects, the control scheme may alternatively determine only one of the first or second engine operating parameter margins and may determine the load sharing based on the operating parameter margin calculated for one engine. In this case, the load sharing may take into account whether the calculated margin is above or below a predetermined threshold. Further, in other exemplary aspects, the control scheme may calculate the load sharing based on the engine operating parameter values ​​without having to calculate the engine operating parameter margins for both engines. Further, in other exemplary aspects, the control scheme may calculate the engine operating parameter margins based on engine identification information instead of receiving data indicating the engine operating parameters, which may indicate, for example, the age of the engine, the time since a maintenance activity, a virtual engine model, a lookup table, etc.

[0085] Reference now Figure 6 , a flow chart of a method 200 for operating a hybrid electric propulsion system of an aircraft according to an exemplary aspect of the present disclosure is provided. The method 200 may be used with one or more exemplary embodiments herein.

[0086] For example, in certain exemplary aspects of method 200, the hybrid electric propulsion system may include a first engine, a second engine, a first electric machine coupled to the first engine, and a second electric machine coupled to one of the first engine or the second engine. In this manner, it should be understood that in certain exemplary aspects, the first engine may be configured similarly to first engine 100A and the second engine may be configured similarly to second engine 100B, or alternatively may be configured in any other suitable manner. In addition, the first electric machine may be configured similarly to Figure 2 The motor 56-1 and Figure 2 56 - 2 in FIG. 5 is coupled to the first engine in a manner similar to that of the motor 56 - 2 in FIG. 5 . Similarly, when coupled to the first engine, the second motor can be coupled to the first engine in a manner similar to that of the motor 56 - 2 in FIG. Figure 2 The second motor may be coupled to the first engine in a similar manner to the other of the motors 56-1 or 56-2 in the embodiment, or when coupled to the second engine, the second motor may be coupled to the first engine in a similar manner to the other of the motors 56-1 or 56-2 in the embodiment. Figure 2 Any one of the motors 56 - 1 or 56 - 2 in the embodiment is connected to the second engine in a similar manner. Of course, in other aspects, the first and second motors can be connected to the first and / or second engines in any other suitable manner.

[0087] like Figure 6As shown, method (200) includes receiving data indicating a first engine operating parameter, a second engine operating parameter, or both at (202); determining a first engine operating parameter margin, a second parameter operating margin, or both at (204); determining a load distribution of the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both at (206); and transmitting a first amount of power to or from the first motor and transmitting a second amount of power to or from the second motor in response to the determined load distribution at (208).

[0088] As will be appreciated from the description herein, method (200) is generally provided to normalize first and second engine operating parameter margins. As such, it will be appreciated that for the exemplary aspects depicted, determining a load distribution between the first engine, the second engine, or both, or between the first engine and the second engine at (206) includes determining a load distribution between the first engine and the second engine at (210) to reduce a difference between the first engine operating parameter margin and the second parameter operating margin, and similarly transmitting a first amount of power to or from the first electric machine and transmitting a second amount of power to or from the second electric machine at (208) includes reducing a difference between the first engine operating parameter margin and the second parameter operating margin at (212).

[0089] More specifically, with specific reference to Figure 6 In the exemplary aspect of FIG. 2 , it will be appreciated that method 200 may be applied to a hybrid electric propulsion system in which a first electric machine is coupled to a first engine and a second electric machine is coupled to a second engine.

[0090] For such exemplary aspects, receiving data indicating a first engine operating parameter, a second engine operating parameter, or both at (202) includes: receiving data indicating a first engine operating parameter of a first engine at (214) while operating the first engine at a first power level; and receiving data indicating a second engine operating parameter of a second engine at (216) while operating the second engine at the first power level. In certain exemplary aspects, the first power level may be an idle power level, a cruising power level, or any other suitable power level.

[0091] In certain exemplary aspects, the first engine operating parameter and the second engine operating parameter can be based at least in part on one or more of: one or more fuel flows to the first and second engines, one or more operating temperatures of the first and second engines, one or more speeds of the first and second engines, one or more shaft torques of the first and second engines, one or more pressure measurements within the first and second engines, one or more thrust outputs of the first and second engines, one or more component identifiers of the first and second engines, one or more estimates or measurements of consumed components or remaining life or performance of the first and second engines, or any combination of these or calculated values ​​derived therefrom.

[0092] Furthermore, for this exemplary aspect, determining the first engine operating parameter margin, the second parameter operating margin, or both at (204) includes determining the first engine operating parameter margin and the second parameter operating margin at (218). It should be understood that, as used herein, the term "margin" generally refers to the difference between a current parameter value and a maximum rated value or a minimum rated value of the parameter for the engine.

[0093] In certain exemplary aspects, the first engine operating parameter margin and the second engine operating parameter margin are both fuel flow margins.

[0094] In certain exemplary aspects, the first engine operating parameter margin and the second engine operating parameter margin are both exhaust temperature margins.

[0095] Still reference Figure 6 In an exemplary aspect of method 200, it should be understood that determining the load distribution between the first engine, the second engine, or both, or between the first engine and the second engine at (206) includes determining the load distribution between the first engine and the second engine based on the difference between the first engine operating parameter margin and the second parameter operating margin at (220).

[0096] Additionally, in at least some exemplary aspects, determining the load distribution between the first engine, the second engine, or both, or between the first engine and the second engine at (206) further includes determining the load distribution between the first engine and the second engine based on a desired operating condition of an aircraft in which the engines are incorporated or of the engines themselves. The desired operating condition may be thrust output of the engines, desired power output / consumption from the engines, etc. For example, the desired operating condition may require a certain amount of power to be extracted from the first and second engines, a desired amount of thrust from the first and second engines, etc.

[0097] Furthermore, as mentioned above, Figure 6The exemplary aspects of the method 200 depicted in are applicable to a hybrid electric propulsion system in which a first electric machine is coupled to a first engine and a second electric machine is coupled to a second engine. In this manner, it should be appreciated that the determined load distribution may include distributing power between the first and second engines, or changing the ratio of power extracted from the first engine and the second engine if power is being extracted from the engines, or changing the ratio of power provided to the first engine and the second engine if power is being added to the engines, or a combination thereof (e.g., extracting power from one engine to an external sink and adding power to the other engine from an external source, transferring power between the engines and adding power to one of the engines from an external source, transferring power between the engines and extracting power from one of the engines to an external sink, etc.).

[0098] In this manner, it should be understood that transferring a first amount of power to or from the first motor and a second amount of power to or from the second motor in response to the determined load distribution at (208) may include transferring the first amount of power from the first motor and the second amount of power to the second motor at (222). For example, in certain exemplary aspects, transferring the first amount of power to or from the first motor and the second amount of power to or from the second motor at (222) may include transferring the first amount of power from the first motor and providing at least a portion of the first amount of power to the second motor at (224). In this manner, the load distribution may include power transfer from the first engine to the second engine.

[0099] Additionally or alternatively, in other exemplary aspects, the hybrid electric propulsion system may include a power source external to the first and second engines (e.g., an electrical energy storage unit (e.g., a battery pack), or a third electric machine coupled to the third engine). In this manner, it will be appreciated that transferring a first amount of power to or from the first electric machine and a second amount of power to or from the second electric machine in response to the determined load distribution at (208) may include transferring power from at least one electric power source to the first electric machine, the second electric machine, or both at (226). For example, transferring a first amount of power to or from the first electric machine and a second amount of power to or from the second electric machine in response to the determined load distribution at (208) may include transferring a first amount of power from the power source to the first electric machine, a second amount of power from the power source to the second electric machine, or both at (228).

[0100] Additionally or alternatively, in still other exemplary aspects, the hybrid electric propulsion system can include or be configured to provide power to an energy receiver (e.g., an aircraft load). In this manner, it will be appreciated that transmitting a first amount of power to or from the first motor and a second amount of power to or from the second motor in response to the determined load distribution at (208) can include transmitting the first amount of power from the first motor and the second amount of power from the second motor at (230).

[0101] For example, in certain exemplary aspects, as noted, the energy receiver can be an aircraft load such that transmitting a first amount of power to or from the first motor and transmitting a second amount of power to or from the second motor in response to the determined load distribution at (208) can include transmitting a first amount of power from the first motor to the aircraft load, and wherein transmitting the second amount of power from the second motor includes transmitting a second amount of power from the second motor to the aircraft load.

[0102] More specifically, for this exemplary aspect, it should be understood that the second power amount is different from the first power amount. For example, the first power amount may constitute between 5% and 45% of the sum of the first and second power amounts, such as at least 10%, such as at least 15%, such as at least 20%, such as at least 25%, such as up to 40%, such as up to 35%, such as up to 35% of the sum of the first and second power amounts.

[0103] Reference now Figure 7 , a flow chart of a method 200 for operating a hybrid-electric propulsion system for an aircraft is provided according to another exemplary aspect of the present disclosure. Figure 7 The method 200 may be similar to Figure 6 An exemplary method 200 of the present invention. For example, in certain exemplary aspects, the method (200) includes receiving data indicating a first engine operating parameter, a second engine operating parameter, or both at (202); determining a first engine operating parameter margin, a second engine operating parameter margin, or both at (204); determining a load distribution between the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both at (206); and transmitting a first amount of power to or from a first electric machine and transmitting a second amount of power to or from a second electric machine in response to the determined load distribution at (208).

[0104] However, for Figure 7In an exemplary aspect, a first electric machine is coupled to a low-pressure system of a first engine, and a second electric machine is coupled to a high-pressure system of the first engine. Further, for such an exemplary aspect, transferring a first amount of power to or from the first electric machine and transferring a second amount of power to or from the second electric machine in response to a determined load distribution at (208) includes transferring power between the high-pressure system and the low-pressure system of the first engine by the first and second electric machines at (236).

[0105] Still referring to Figure 7 , it should be understood that method 200 may further include aspects for normalizing the margins between multiple engines or ensuring that the thrust forces generated from two engines are substantially the same. For example, Figure 6 an exemplary aspect of method 200 further includes modifying non-essential bleed air provided by the first engine, the second engine, or both in response to a determined load distribution at (232), and controlling the thrust difference between the first and second gas turbine engines at (234). These method steps may further be applied to Figure 6 the exemplary aspects of method 200 depicted in

[0106] This written description uses examples to disclose the invention, including the best mode, and also enables those skilled in the art to practice the invention, including making and using any device or system and performing any incorporated method. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples include structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims, then these other examples are intended to fall within the scope of the claims.

[0107] Further aspects of the invention are provided by the subject matter of the following articles:

[0108] A method for operating a hybrid electric propulsion system for an aircraft, the hybrid electric propulsion system comprising a first engine, a second engine, a first motor coupled to the first engine, and a second motor coupled to one of the first engine or the second engine, the method comprising: receiving data indicating a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin, a second parameter operating margin, or both; determining a load distribution between the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both; and transmitting a first amount of power to or from the first motor and a second amount of power to or from the second motor in response to the determined load distribution.

[0109] A method according to one or more of these clauses, wherein the second motor is coupled to the second engine, and wherein receiving data indicating the first engine operating parameter, the second engine operating parameter, or both includes: receiving data indicating a first engine operating parameter of the first engine while operating the first engine at a first power level; receiving data indicating a second engine operating parameter of the second engine while operating the second engine at the first power level; and wherein determining the first engine operating parameter margin, the second parameter operating margin, or both includes determining the first engine operating parameter margin and the second parameter operating margin.

[0110] A method as in one or more of these clauses, wherein the second amount of power is different than the first amount of power.

[0111] A method according to one or more of these clauses, wherein determining the first engine operating parameter margin, the second parameter operating margin, or both includes determining the first engine operating parameter margin and the second parameter operating margin, and wherein determining the load distribution between the first engine, the second engine, or both, or the first engine and the second engine includes determining the load distribution between the first engine and the second engine to reduce the difference between the first engine operating parameter margin and the second parameter operating margin.

[0112] A method according to one or more of these clauses, wherein the first engine operating parameter and the second engine operating parameter are based at least in part on one or more of: one or more fuel flows to the first engine and the second engine, one or more operating temperatures of the first engine and the second engine, one or more speeds of the first engine and the second engine, one or more shaft torques of the first engine and the second engine, one or more pressure measurements within the first engine and the second engine, one or more thrust outputs of the first engine and the second engine, one or more component identifiers of the first engine and the second engine, one or more estimates or measurements of consumed components or remaining life or performance of the first engine and the second engine, or any combination of these or calculated values ​​derived therefrom.

[0113] The method according to one or more of these clauses, wherein the first engine operating parameter margin is less than the first engine operating parameter margin, and wherein the second power amount is greater than the first power amount.

[0114] The method according to one or more of these clauses, wherein the first electric machine is coupled to a low pressure system of the first engine, and wherein the second electric machine is coupled to a high pressure system of the first engine.

[0115] A method according to one or more of these clauses, wherein transmitting the first amount of power to or from the first motor and transmitting the second amount of power to or from the second motor includes transmitting the first amount of power from the first motor and transmitting the second amount of power to the second motor.

[0116] The method according to one or more of these clauses, wherein the first engine operating parameter margin and the second engine operating parameter margin are both fuel flow margins.

[0117] The method according to one or more of these clauses, wherein the first engine operating parameter margin and the second engine operating parameter margin are both exhaust temperature margins.

[0118] A method according to one or more of these clauses, wherein transmitting the first amount of power to or from the first motor and transmitting the second amount of power to or from the second motor includes transmitting the first amount of power from the first motor and providing at least a portion of the first amount of power to the second motor.

[0119] A method according to one or more of these clauses, wherein transmitting the first amount of power to or from the first motor and transmitting the second amount of power to or from the second motor includes transmitting power from at least one electric power source to the first motor, the second motor, or both.

[0120] A method according to one or more of these clauses, wherein the second motor is connected to the second engine, and wherein transmitting the first amount of power to or from the first motor and transmitting the second amount of power to or from the second motor includes: transmitting a first amount of electric power from the first motor; and transmitting a second amount of power from the second motor, and wherein the second amount of power is different from the first amount of power.

[0121] A method according to one or more of these clauses, wherein transmitting the first amount of electrical power from the first motor comprises transmitting the first amount of electrical power from the first motor to an aircraft load, and wherein transmitting the second amount of electrical power from the second motor comprises transmitting the second amount of electrical power from the second motor to the aircraft load.

[0122] The method of one or more of these clauses, wherein the first power amount is between 5% and 45% of a sum of the first power amount and the second power amount.

[0123] The method according to one or more of these clauses, further comprising controlling a thrust difference between the first gas turbine engine and the second gas turbine engine.

[0124] A method according to one or more of these clauses, wherein determining the first engine operating parameter margin, the second parameter operating margin, or both includes determining the first engine operating parameter margin and the second parameter operating margin, and wherein transmitting the first amount of power to or from the first motor and transmitting the second amount of power to or from the second motor includes reducing a difference between the first engine operating parameter margin and the second parameter operating margin.

[0125] A method according to one or more of these clauses, wherein determining the load distribution between the first engine, the second engine, or both, or between the first engine and the second engine includes determining the load distribution between the first engine and the second engine based on a difference between the first engine operating parameter margin and the second parameter operating margin.

[0126] The method of one or more of these clauses further comprises modifying non-essential bleed air provided by the first engine, the second engine, or both in response to the determined load distribution.

[0127] A system comprising a first engine, a second engine, a first motor coupled to the first engine, a second motor coupled to the first engine or the second engine, and a controller comprising a memory and one or more processors, the memory storing instructions that, when executed by the one or more processors, cause the system to: receive data indicating a first engine operating parameter, a second engine operating parameter, or both; determine a first engine operating parameter margin, a second parameter operating margin, or both; determine a load distribution between the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both; and transmit a first amount of power to or from the first motor and a second amount of power to or from the second motor in response to the determined load distribution.

[0128] The system according to one or more of these clauses, wherein the instructions, when executed by the one or more processors, further cause the system to perform one or more steps of the method of one or more of these clauses.

Claims

1. A method for operating a hybrid electric propulsion system of an aircraft, It is characterized in that The hybrid electric propulsion system includes a first engine, a second engine, a first electric machine coupled to the first engine, and a second electric machine coupled to one of the first engine or the second engine, the method comprising: receiving data indicative of a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin and a second engine operating parameter margin; determining a load distribution between the first engine and the second engine based on the first engine operating parameter margin and the second engine operating parameter margin to reduce a difference between the first engine operating parameter margin and the second engine operating parameter margin; and A first amount of power is transferred to or from the first electric machine and a second amount of power is transferred to or from the second electric machine in response to the determined load distribution to reduce the difference between the first engine operating parameter margin and the second engine operating parameter margin.

2. The method according to claim 1, It is characterized in that wherein the second electric machine is coupled to the second engine, and wherein receiving data indicative of the first engine operating parameter, the second engine operating parameter, or both comprises: receiving data indicative of a first engine operating parameter of the first engine while operating the first engine at a first power level; Data indicative of a second engine operating parameter of the second engine is received while operating the second engine at the first power level.

3. The method according to claim 2, It is characterized in that Wherein the second power amount is different from the first power amount.

4. The method according to claim 2, It is characterized in that Wherein the first engine operating parameter and the second engine operating parameter are based at least in part on one or more of: one or more fuel flows to the first engine and the second engine, one or more operating temperatures of the first engine and the second engine, one or more speeds of the first engine and the second engine, one or more shaft torques of the first engine and the second engine, one or more pressure measurements within the first engine and the second engine, one or more thrust outputs of the first engine and the second engine, one or more component identifiers of the first engine and the second engine, one or more estimates or measurements of consumed components or remaining life or performance of the first engine and the second engine, or any combination of these or calculated values ​​derived therefrom.

5. The method according to claim 2, It is characterized in that Wherein the first engine operating parameter margin is less than the second engine operating parameter margin, and wherein the second power amount is greater than the first power amount.

6. The method according to claim 1, It is characterized in that Wherein the first electric machine is coupled to a low pressure system of the first engine, and wherein the second electric machine is coupled to a high pressure system of the first engine.

7. The method according to claim 6, It is characterized in that Wherein transmitting the first amount of power to or from the first electric machine and transmitting the second amount of power to or from the second electric machine comprises transmitting the first amount of power from the first electric machine and transmitting the second amount of power to the second electric machine.

8. The method according to claim 1, It is characterized in that Wherein the first engine operating parameter margin and the second engine operating parameter margin are both fuel flow margins.

9. The method according to claim 1, It is characterized in that The first engine operating parameter margin and the second engine operating parameter margin are both exhaust temperature margins.

10. The method according to claim 1, It is characterized in that Wherein transmitting the first amount of power to or from the first electric machine and transmitting the second amount of power to or from the second electric machine includes transmitting the first amount of power from the first electric machine and providing at least a portion of the first amount of power to the second electric machine.

11. The method according to claim 1, It is characterized in that Wherein transmitting the first amount of power to or from the first electric machine and transmitting the second amount of power to or from the second electric machine includes transmitting power from at least one electric power source to the first electric machine, the second electric machine, or both.

12. The method according to claim 1, It is characterized in that wherein the second electric machine is coupled to the second engine, and wherein transmitting the first amount of power to or from the first electric machine and transmitting the second amount of power to or from the second electric machine comprises transmitting a first amount of electrical power from the first motor; as well as A second amount of power is transmitted from the second electric machine, and wherein the second amount of power is different from the first amount of power.

13. The method according to claim 12, It is characterized in that Wherein transmitting the first amount of electrical power from the first electric machine comprises transmitting the first amount of electrical power from the first electric machine to an aircraft load, and wherein transmitting the second amount of electrical power from the second electric machine comprises transmitting the second amount of electrical power from the second electric machine to the aircraft load.

14. The method according to claim 13, It is characterized in that The first power amount accounts for between 5% and 45% of the sum of the first power amount and the second power amount.

15. The method according to claim 1, It is characterized in that Further including: A thrust difference between the first engine and the second engine is controlled.

16. The method according to claim 1, It is characterized in that Wherein determining the load distribution between the first engine, the second engine, both, or the first engine and the second engine includes determining the load distribution between the first engine and the second engine based on a difference between the first engine operating parameter margin and the second engine operating parameter margin.

17. The method according to claim 1, It is characterized in that Further comprising modifying non-essential bleed air provided by the first engine, the second engine, or both in response to the determined load distribution.

18. A system, It is characterized in that The system includes a first engine, a second engine, a first electric machine coupled to the first engine, a second electric machine coupled to the first engine or the second engine, and a controller, the controller including a memory and one or more processors, the memory storing instructions that, when executed by the one or more processors, cause the system to perform the following operations: receiving data indicative of a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin and a second engine operating parameter margin; determining a load distribution between the first engine and the second engine based on the first engine operating parameter margin and the second engine operating parameter margin to reduce a difference between the first engine operating parameter margin and the second engine operating parameter margin; as well as A first amount of power is transferred to or from the first electric machine and a second amount of power is transferred to or from the second electric machine in response to the determined load distribution to reduce the difference between the first engine operating parameter margin and the second engine operating parameter margin.

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